Ex tempore (latin „out of the moment“) describes action offhand without following a script, especially with speech and stage acting. Sometines the term is used for prepared issues, which are not written to the official hand-out version of a text for public speech.
As with impromptu prose, there are forms and styles for verses, poems and songs, with which ex tempore performing is traditional, as e.g. Couplet (FR), Gstanzl (AT), Limerick (EIR).
Ex tempore is a traditional style on stage and in public performance, though valued rather different. Capability and courage to perform ex tempore are valued as talent for improvisation, but on the other hand dreaded by colleagues, authors and censors.
For speech, in comedy, in imprompty theatre and in socio-political cabaret, ex tempore is often challenged by spontaneous response from the audience.